European states initially developed different policy responses to protect merchant ships crossing the Indian Ocean from pirates: while some countries immediately employed private security companies (PSCs), others resorted to vessel protection detachments (VPDs) or devised a dual approach which only authorizes PSCs as a last resort. By 2018, however, all states with a sizeable shipping industry had de facto privatized vessel protection. This chapter conceptualises this process as a form of institutional isomorphism. By examining British, Italian, and Dutch vessel protection policies, we show that the turn to PSCs was shaped by a convergence of coercive, normative, and mimetic isomorphism tendencies. Specifically, the widespread privatization of vessel protection was informed by the economic, manpower, and political constraints attached to the use of VPDs, the perceived effectiveness and growing legitimacy of PSCs, and the deliberate emulation of vessel protection policies that had already been implemented successfully by other states.